There is a growing body of evidence that domesticated animals and in particular laboratory animals exhibit behaviors that in humans are associated with sensory deprivation, and depression. These abnormal behaviors not only impact the well-being of an individual animal but also have implications in studies involving such an animal owing to the physiological effects of sensory deprivation and depression. In humans, sensory deprivation and depression have an effect on metabolism, cognitive function, immune response and other parameters relevant to clinical studies. The ability to provide a laboratory animal with a degree of mental stimulation is hampered by the requirements of study protocols that attempt to avoid introduction of new reaction variables, as well as the requirement in many instances that only sterilized materials be brought into contact with a laboratory animal. Captive animals deserve an environment which is rich in social opportunity, mental stimulation, and physical challenges. Sterility conditions are typically enforced in instances where an animal has been immunocompromised or otherwise carries a genetic defect rendering an animal vulnerable to disease or infection.
With laboratory study requirements, litter provided to absorb animal urine and desiccate fecal material is one of a limited number of opportunities to provide a source of stimulation to a confined laboratory animal. Prior art attempts have been made to include folded squares of paper with the intention that the animal would occupy time delaminating and chewing or unfolding the small chips of paper. Unfortunately, such attempts met with limited success owing to the disinterest of mice (especially male species) and rats confined within laboratory cages to actually play with the folded squares of paper. The 1985 amendments to the Animal Welfare Act included provisions for the promotion of the psychological well-being of nonhuman primates and for exercise for dogs. Today, many research, teaching and testing facilities have established environmental enrichment programs for all animal species. (awic.nal.usda.gov/nal_display/index) are representative of this effort.
Nest building is natural activity of rodents, especially mice. Nest building is a form of psychological enrichment and a vital part of needs for a mouse environment. Mice tend to be most comfortable at a temperature of 30 degrees Celsius. Often laboratories housing mice are maintained at a temperature of 21 to 24 degrees Celsius. Mice build nests in order to thermoregulate. Through the maintenance of mice at a comfortable temperature, mice consume less food, have higher pup yields, and experience less overall stress.
Thus, there exists a need for an animal litter product that engages the attention of a laboratory animal to occupy time and alleviate some of the symptoms associated with sensory deprivation and thermal disregulation. There further exists a need for such a litter capable of being sterilized and still functioning as an effective animal litter product.